SI-6967 Fix ClassTag unapply for primitives

This commit fixes the behavior of ClassTag's Any-accepting unapply
overload. Previously, ClassTag had overloads of unapply that accepted
all of the Java primitive aliases (language-supported magic classes
extending AnyVal), as well as an implementation that accepted an Any.
All of the AnyVal-accepting (more specific) versions of the methods
worked correctly. However, the Any-accepting version incorrectly handled
these types. For example, ClassTag.Int.unapply(3) would return Some(3)
(through the Int-accepting overload), while ClassTag.Int.unapply(3: Any)
would return None (through the Any-accepting overload). This commit
unifies these behaviors, making ClassTag.Int.unapply(3: Any) return
Some(3). It accomplishes this by adding a pattern match on the type of
that method's argument, which will delegate to one of the
more-specifically-typed overloads if possible. It also improves the
formatting of the code a bit.

One thing to note (though I doubt anyone will ever do this based on this
message) is that the AnyVal-subtype-accepting overloads should be
removed in Scala 2.12, as they are unneeded. I placed a  note to this
effect into the code.

3 files changed, 67 insertions, 31 deletions

diff --git a/test/files/run/t6318_primitives.check b/test/files/run/t6318_primitives.check
index b330f91276..4bc5e598eb 100644
--- a/test/files/run/t6318_primitives.check
+++ b/test/files/run/t6318_primitives.check
@@ -1,36 +1,54 @@
-true
+Checking if byte matches byte
 Some(1)
-false
+Checking if byte matches short
 None
-true
+Checking if class java.lang.Byte matches byte
 Some(1)
-false
+Checking if short matches short
+Some(1)
+Checking if short matches char
 None
-true
+Checking if class java.lang.Short matches short
+Some(1)
+Checking if char matches char
 Some(
)
-false
+Checking if char matches int
 None
-true
+Checking if class java.lang.Character matches char
+Some(
)
+Checking if int matches int
 Some(1)
-false
+Checking if int matches long
 None
-true
+Checking if class java.lang.Integer matches int
 Some(1)
-false
+Checking if long matches long
+Some(1)
+Checking if long matches float
 None
-true
+Checking if class java.lang.Long matches long
+Some(1)
+Checking if float matches float
 Some(1.0)
-false
+Checking if float matches double
 None
-true
+Checking if class java.lang.Float matches float
 Some(1.0)
-false
+Checking if double matches double
+Some(1.0)
+Checking if double matches boolean
 None
-true
+Checking if class java.lang.Double matches double
+Some(1.0)
+Checking if boolean matches boolean
 Some(true)
-false
+Checking if boolean matches void
 None
-true
+Checking if class java.lang.Boolean matches boolean
+Some(true)
+Checking if void matches void
 Some(())
-false
+Checking if void matches byte
 None
+Checking if class scala.runtime.BoxedUnit matches void
+Some(())
diff --git a/test/files/run/t6318_primitives.scala b/test/files/run/t6318_primitives.scala
index 30f27120b3..bc8ec88359 100644
--- a/test/files/run/t6318_primitives.scala
+++ b/test/files/run/t6318_primitives.scala
@@ -2,70 +2,88 @@ import scala.reflect.{ClassTag, classTag}
 
 object Test extends App {
   def test[T: ClassTag](x: T) {
-    println(classTag[T].runtimeClass.isAssignableFrom(x.getClass))
+    println(s"Checking if ${x.getClass} matches ${classTag[T].runtimeClass}")
     println(classTag[T].unapply(x))
   }
 
   {
     val x = 1.toByte
-    println(ClassTag.Byte.runtimeClass.isAssignableFrom(x.getClass))
+    println(s"Checking if ${x.getClass} matches ${classTag[Byte].runtimeClass}")
     println(ClassTag.Byte.unapply(x))
+    println(s"Checking if ${x.getClass} matches ${classTag[Short].runtimeClass}")
+    println(ClassTag.Short.unapply(x))
     test(x)
   }
 
   {
     val x = 1.toShort
-    println(ClassTag.Short.runtimeClass.isAssignableFrom(x.getClass))
+    println(s"Checking if ${x.getClass} matches ${classTag[Short].runtimeClass}")
     println(ClassTag.Short.unapply(x))
+    println(s"Checking if ${x.getClass} matches ${classTag[Char].runtimeClass}")
+    println(ClassTag.Char.unapply(x))
     test(x)
   }
 
   {
     val x = 1.toChar
-    println(ClassTag.Char.runtimeClass.isAssignableFrom(x.getClass))
+    println(s"Checking if ${x.getClass} matches ${classTag[Char].runtimeClass}")
     println(ClassTag.Char.unapply(x))
+    println(s"Checking if ${x.getClass} matches ${classTag[Int].runtimeClass}")
+    println(ClassTag.Int.unapply(x))
     test(x)
   }
 
   {
     val x = 1.toInt
-    println(ClassTag.Int.runtimeClass.isAssignableFrom(x.getClass))
+    println(s"Checking if ${x.getClass} matches ${classTag[Int].runtimeClass}")
     println(ClassTag.Int.unapply(x))
+    println(s"Checking if ${x.getClass} matches ${classTag[Long].runtimeClass}")
+    println(ClassTag.Long.unapply(x))
     test(x)
   }
 
   {
     val x = 1.toLong
-    println(ClassTag.Long.runtimeClass.isAssignableFrom(x.getClass))
+    println(s"Checking if ${x.getClass} matches ${classTag[Long].runtimeClass}")
     println(ClassTag.Long.unapply(x))
+    println(s"Checking if ${x.getClass} matches ${classTag[Float].runtimeClass}")
+    println(ClassTag.Float.unapply(x))
     test(x)
   }
 
   {
     val x = 1.toFloat
-    println(ClassTag.Float.runtimeClass.isAssignableFrom(x.getClass))
+    println(s"Checking if ${x.getClass} matches ${classTag[Float].runtimeClass}")
     println(ClassTag.Float.unapply(x))
+    println(s"Checking if ${x.getClass} matches ${classTag[Double].runtimeClass}")
+    println(ClassTag.Double.unapply(x))
     test(x)
   }
 
   {
     val x = 1.toDouble
-    println(ClassTag.Double.runtimeClass.isAssignableFrom(x.getClass))
+    println(s"Checking if ${x.getClass} matches ${classTag[Double].runtimeClass}")
     println(ClassTag.Double.unapply(x))
+    println(s"Checking if ${x.getClass} matches ${classTag[Boolean].runtimeClass}")
+    println(ClassTag.Boolean.unapply(x))
     test(x)
   }
 
   {
     val x = true
-    println(ClassTag.Boolean.runtimeClass.isAssignableFrom(x.getClass))
+    println(s"Checking if ${x.getClass} matches ${classTag[Boolean].runtimeClass}")
     println(ClassTag.Boolean.unapply(x))
+    println(s"Checking if ${x.getClass} matches ${classTag[Unit].runtimeClass}")
+    println(ClassTag.Unit.unapply(x))
     test(x)
   }
 
   {
     val x = ()
-    println(ClassTag.Unit.runtimeClass.isAssignableFrom(x.getClass))
+    println(s"Checking if ${x.getClass} matches ${classTag[Unit].runtimeClass}")
     println(ClassTag.Unit.unapply(x))
+    println(s"Checking if ${x.getClass} matches ${classTag[Byte].runtimeClass}")
+    println(ClassTag.Byte.unapply(x))
     test(x)
   }
-}
\ No newline at end of file
+}
diff --git a/test/files/run/virtpatmat_typetag.check b/test/files/run/virtpatmat_typetag.check
index cac9d9a4d6..00df8b5e81 100644
--- a/test/files/run/virtpatmat_typetag.check
+++ b/test/files/run/virtpatmat_typetag.check
@@ -1,9 +1,9 @@
-1 is not a Int; it's a class java.lang.Integer
+1 is a Int
 1 is a java.lang.Integer
 1 is not a java.lang.String; it's a class java.lang.Integer
 true is a Any
 woele is a java.lang.String
-1 is not a Int; it's a class java.lang.Integer
+1 is a Int
 1 is a java.lang.Integer
 1 is not a java.lang.String; it's a class java.lang.Integer
 true is a Any